//#include "stdafx.h"

/*
* File name:		sp_ienv.c
* History:             Modified from lapack routine ILAENV
*/
#include "slu_Cnames.h"

int
sp_ienv(int ispec)
{
	/*
	Purpose   
	=======   

	sp_ienv() is inquired to choose machine-dependent parameters for the
	local environment. See ISPEC for a description of the parameters.   

	This version provides a set of parameters which should give good,   
	but not optimal, performance on many of the currently available   
	computers.  Users are encouraged to modify this subroutine to set   
	the tuning parameters for their particular machine using the option   
	and problem size information in the arguments.   

	Arguments   
	=========   

	ISPEC   (input) int
	Specifies the parameter to be returned as the value of SP_IENV.   
	= 1: the panel size w; a panel consists of w consecutive
	columns of matrix A in the process of Gaussian elimination.
	The best value depends on machine's cache characters.
	= 2: the relaxation parameter relax; if the number of
	nodes (columns) in a subtree of the elimination tree is less
	than relax, this subtree is considered as one supernode,
	regardless of their row structures.
	= 3: the maximum size for a supernode;
	= 4: the minimum row dimension for 2-D blocking to be used;
	= 5: the minimum column dimension for 2-D blocking to be used;
	= 6: the estimated fills factor for L and U, compared with A;

	(SP_IENV) (output) int
	>= 0: the value of the parameter specified by ISPEC   
	< 0:  if SP_IENV = -k, the k-th argument had an illegal value. 

	===================================================================== 
	*/
	int i;

	switch (ispec) {
	case 1: return (10);
	case 2: return (5);
	case 3: return (100);
	case 4: return (200);
	case 5: return (40);
	case 6: return (20); //original: 20
	}

	/* Invalid value for ISPEC */
	i = 1;
	xerbla_("sp_ienv", &i);
	return 0;

} /* sp_ienv_ */

